Method of producing amorphous metal tapes

ABSTRACT

A method is disclosed for the production of amorphous metal tapes by rolling and cooling a molten metal stream between the contact faces of one roll and one metal belt. Tapes having controlled dimensions may be obtained.

This is a continuation, of application Ser. No. 883,859, filed Mar. 6,1978 and now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to an improved method of producing amorphousmetal tapes. It is known that certain alloy melts usually containing oneor more metalloids C, B, Si, P, Ge, etc. in amounts of about 20 to 40atomic % can be made to solidify in the amorphous state by rapidcooling. Because of high cooling rates required to obtain the amorphousstate from the liquid, amorphous metals must have at least one dimensionsmall enough to ease the extract of heat from the melt, hence they areproduced in the form of a tape.

Various laboratory techniques have been proposed to provide rapidcooling by spreading a melt in a thin layer against a cold substrate.Examples of these procedures include, among others, the single rollmethod, the centrifugal method, and the twin (double) roll method.

The single roll method consists in supplying a molten metal onto thesurface of a rotating metal roll, in the form of a thin film or finestream, so that the molten metal may be rapidly cooled by the roll tobecome a solidified tape. However, this method is not suitable forproducing a tape having a large width nor for obtaining a tape having auniform thickness.

The centrifugal method makes use of the inner surface of a rotatinghollow metal cylinder as the cooling surface and is based upon a similarprinciple underlying the single roll method.

In these two methods the free surface of the melt receives no constraintduring solidification so that the produced tapes often have uneventhicknesses in the width direction. In addition, since the force exertedon the tape to press it onto the cooling surface is weak, recesses orindentations are likely to be formed on the tape surface. Still anotherdisadvantage is that undulations are apt to be formed in thelongitudinal direction of the tape.

Further, the single roll method is capable of producing an amorphousmetal tape only with selected compositions of the molten metal.

In the third method, i.e. the double roll method, a jet stream of amolten metal is introduced into the nip of a pair of rolls rotating at ahigh speed, and rolled and cooled simultaneously. This method requiresfrequent polishing of roll surfaces. In addition, when the rolls areused continuously for processing a long tape, the rolls soon lose theircooling capability, especially in the production of a wide tape. It isin no way possible to forcibly cool the rolls, by any known method.

Another problem inherent in this double roll method is the difficulty inbringing and maintaining the two rolls exactly parallel to each other.

Thus, the width of the tape obtainable by the double roll method isusually as small as 2 to 3 mm, and tapes having a width exceeding 10 mmcan hardly be obtained unless a special technique is employed in themethod of establishing a uniform roll contact. In addition, thereproducibility of tape dimensions in this method is poor.

Furthermore, since there is no escape between two rolls for theroughness of the roll surfaces, the roll surfaces are easily damaged.The defect of the roll surfaces, once it is formed, is copied onto thetape surface as protuberances. To avoid this, it is required tofrequently polish the roll surfaces, which impairs the workingefficiency considerably.

In order to overcome the above described shortcomings or drawbacks ofthe prior art, the present inventors formerly proposed an indirectdouble roll method in which a molten metal jet is rolled and cooledbetween two running metal belts backed up by two rotating rolls. Thisindirect double roll method is effective in that as far as the coolingcapacity is concerned, it can afford an effect equivalent to thatobtainable by the use of large diameter rolls, provided the lengths ofthe metal belts are made long enough. However, this advantage is offsetby the variation in the roll gap and the belt thicknesses which add updirectly to the tape thickness to be produced. In addition, thistechnique requires a complicated mechanism for driving the belts, androlls without slippage.

For these reasons, this technique is also unsatisfactory.

DESCRIPTION OF THE INVENTION

Under these circumstances, the present inventors have succeeded inobtaining a novel method which overcomes the problems and shortcomingsinherent in the conventional single and double roll methods, as well asthe indirect double roll method.

According to one aspect of the invention, there is provided a method ofproducing long and wide amorphous metal tapes having superiordimensional accuracy wherein a molten metal jet of a composition capableof forming an amorphous metal upon rapid cooling is introduced into thenip formed by one rotating working roll and one contiguously runningmetal belt, and rolled and cooled, the contact between the roll and thebelt being effected by providing a second, back-up, roll capable ofexerting pressure on the metal belt.

Thus, the method in accordance with the invention is substantiallydifferent from the conventional single and double roll methods in whichthe molten metal is cooled by a roll surface or roll surfaces in thatthe cooling of the molten metal is achieved materially by the metal beltalone. In other words, it is a critical feature of the invention thatthe cooling by the working roll is only subsidiary, as compared withthat by the metal belt. Thus, the working roll may be of metal orceramic. Further, since the cold belt portion is continuously fed toform the cooling surface, the length of the obtainable tape is limitedonly by the length of the cooling belt used and no special technique isrequired in the method of supplying a molten melt.

Furthermore, according to the invention, the dimensional accuracy of theproduct tape is greatly enhanced simply by using a high precisionworking roll, because the flexible belt having a smooth surface canalways follow up the rolling surface of the working roll, thus ensuringconstant and parallel contact throughout the rolling region between theworking roll and the metal belt.

Fluctuations in the tape thickness are diminished by providing amechanism by which to resiliently press one roll, via the metal beltagainst the other by means of, say, a spring or a hydraulic or pneumaticcylinder. In this way, any disturbance arising from the belt thicknesschange can be absorbed into an elastic displacement of the pressingroll.

As an alternative measure which is more simple and more effective inobtaining the improved dimensional accuracy of the tape than the abovepressing, it is proposed to use an elastic roll as the back-up rollwhich backs up the metallic belt from behind toward the working roll,thus providing a better and unchanging contact between the working rolland the metal belt.

The amorphous metal tape on which the present invention is focussedusually has a thickness of 10 to 50μ, and it is required that thethickness fluctuation fall within ±2μ for a mean thickness of 25μ.

By the method of the invention making use of an elastic roll for thebacking up of the metal belt, such a severe dimensional control isachieved with ease and no additional processing is necessary such aspolishing or lapping for providing the tape with a smooth and uniformsurface.

The remarkable improvement in the dimensional control of the tapeafforded by the use of an elastic back-up roll for backing up the metalbelt is attributed partly to the faithful following up of the metal beltto the working roll surface, but also to the capability of the back-uproll to absorb any slight misalignment of the roll axes as well as anyslight variation in the metal belt thickness.

Another advantage of the invention derived from the use of an elasticroll is that the nip area between the working roll and the metal belt isincreared from a line contact to a face contact, thus affording a moreeffective rolling and cooling to the molten metal.

Furthermore, the elastic nature of the back-up roll helps to relieveexcessive accidental loads from acting on the working roll and the metalbelt, with the consequent result that the damage of these surfaces canbe minimized or avoided.

When an elastic roll is used as the back-up roll, the elasticity of theroll is preferably small. Thus, for instance, a composite roll having aninner metal core covered with a hard rubber layer is preferred. In sucha case, a thickness of the rubber layer two to three times as large asthat of the belt, which usually has a thickness of 0.5 mm or smaller, issufficient. Too large thicknesses of the rubber layer weaken thepressure to be exerted on the belt and cause an undesirable deformationof the roll during operation, and, therefore, is not preferred.

Alternatively, the back-up roll may be formed by simply winding a gumtape to one to three layers around a metal roll of 50 to 100 mmdiameter, so that the layers of the gum tape may have a total thicknessof about 1 mm or less. This back-up roll provides quite a satisfactoryresult, provided that the seam effect is ignored. A largerwear-resistant property will be ensured if a teflon layer is formedaround a metal roll and then machined and finished.

On the other hand, the metal belt, which plays an essential roll in thepresent invention, must have a good surface smoothness, mechanicalstrength and flexibility, be it endless or with ends. From a practicalpoint of view, the thickness is preferably 0.5 mm or less in case of acopper alloy belt, while it is preferably 0.4 mm or less with a steelbelt. A width of two times as large as that of the desired tape willsuffice.

It is neither possible nor necessary to define the material andthickness of the belt strictly, because the cooling capacity of the beltdepends not only on the material and thickness adopted but also on otherconditions such as rolling pressure, rolling speed, rolling system, meltcomposition and so forth. Indeed, any commercially available thin belthaving a melting point of about 800° C. or above will do.

It must be stated, however, that, as a rule, a thick and narrow tape isproduced with the use of a thick and high heat conductivity belt and athin and wide tape with a thin and poor heat conductivity belt. Thisfact may, in turn, be used in controlling the tape dimensions.

The working roll of the invention may be of either metal or ceramic. Inthe selection of roll materials, consideration need not be given tocooling capacity which is ensured by the metal belt, nor to mechanicalstrength. The rolls suffer practically no load during processing. Thus,ordinary irons and steels make good rolls. Much softer copper or copperrolls are also usable. In general, rolls having a hard surface arepreferable. Rolls may be optionally hardened by heat treatment orplating.

While metal rolls have the advantage of being inexpensive and easy tofabricate, they have also the disadvantage of being weak to thermal weardue to prolonged contact with a high temperature melt, thus demandingfrequent polishing of the roll surface, as well as the preparation of alarge number of stock rolls.

Heat-wear is observed to a varying degree in all metallic materialstested such as carbon steel (ASTM 1045), hot tool steels (ASTM H21, ASTMD2) and spring steel (ASTM 52100).

Since the surface roughness of a tape is a replica of that of a workingroll used, resistance to thermal wear constitutes a requisite of utmostimportance.

This disadvantage with metal working rolls can be overcome by the use ofa ceramic roll. Ceramics exhibit a good resistance against heat and arenever worn down nor corroded even when in prolonged contact with themolten metal.

Therefore, once a smooth surface is produced, the roll can stand longuse without requiring repeated polishing.

In general, ceramic materials exhibit poor strength against mechanicaland thermal impacts. Fortunately, the process of the invention is suchthat the working roll suffers practically no load or mechanical impact.In addition, experiments revealed that thermal impact causes no troublewith a ceramic roll. To ensure good thermal-impact resistance, asleeve-like ceramic material is preferably combined with a metallic coreto form a composite roll.

Any ceramic materials that can stand the temperature of the molten metalcan be used. They may be chosen in consideration of the composition ofthe molten metal to be rolled, required tape surface, roughness, ease infabrication and maintenance, durability and other economicalrequirements.

Ordinary oxide ceramics such as alumina, beryllia, titania, zirconia,magnesia, as well as silica including quartz, may be used as the rollmaterial. Fine grained sintered alumina and molten ruby and sapphire aremost desirable.

Further, the ceramic materials may be carbide ceramics (TiC, SiC),nitride ceramics (AIN,BN) or boride ceramics. As an alternative, a steelroll surface may be suitably treated to provide a surface layer of aboride, nitride, or carbide.

According to a second aspect of the invention, there is provided animproved method of producing long and wide amorphous metal tapes havingsuperior dimensional accuracy wherein a molten metal jet of acomposition capable of forming an amorphous metal upon rapid cooling isintroduced into the nip formed by one rotating working roll and onecontiguously running metal belt, and rolled and cooled, the contactbetween the roll and the belt being effected by providing a second,back-up, roll capable of exerting pressure on the metal belt and furtherby providing a third guide roll at a position closer to the working rollthan to the back-up roll so that the contact may extend over part of theworking roll surface on the delivery side (see, e.g., FIGS. 2 and 3).

The object of this latter method is to further enhance the rolling andcooling capacity of the method of the first aspect in which the rollingand cooling of the molten metal is effected only over a narrow regionnear the roll entrance.

According to this method of the second aspect, the rolling and coolingof the molten metal is performed over an extended region where the metalbelt engages the working roll. The back-up roll which presses the metalbelt toward the working roll prescribes the position at which the metalbelt commences to cooperate with the working roll, while the guide rollacts to prescribe the position at which the cooperation of the workingroll and the metal belt is terminated.

Consequently, according to the method of the second aspect, the area ofrolling and cooling of the molten metal is further spread to a largerarea, thus providing the melt with a better rolling and cooling. It nowbecomes possible to friction drive all the rolls by one belt alonewithout slippage, a simplifying feature of technical importance.

The length over which the metal belt cooperates with the working rollmay be varied depending on the rigidity of the belt, running speed,moment of inertia of the working roll, pressure by which the metal beltis pressed onto the working roll, tension residing in the metal belt andso forth. However, one tenth of the entire circumference of the workingroll is sufficient, and the tension applied to the metal belt may be assmall as several kilogrammes.

At the same time, as is the case of the method of the first aspect, theprecision of the product tape is remarkably enhanced by adopting anelastic roll as the back-up roll of the metal belt.

It is to be understood that in carrying out the method of the invention,means for adjusting the clearance between the metal belt and the back-uproll, means for applying a tension to the metal belt, means for drivingthe belt, means for supplying the molten metal and so forth are suitablycombined and equipped to meet the object of the invention.

What has been said about the working roll and the cooling belt in theexplanation of the method of the first aspect, applies, withoutalternations, to the method of the second aspect.

According to a third aspect of the invention, the method of the secondaspect is further improved to avoid the accident attributable to aclinging of the tape to the roll, by adopting a gas jetting means (e.g.,as shown in FIG. 5)

More specifically, according to the third aspect of the invention, thereis provided a method of producing an amorphous metal tape wherein aworking roll is rotated in contact with a metal belt which is backed upby a back-up roll and made to run, while a guide roll around which themetal belt goes is disposed at the delivery side of the metal belt andat a position closer to the working roll than to the back-up roll, sothat the metal belt may run in contact over at least a part of thesurface of working roll, so that a molten metal supplied to a point atwhich the working roll and the metal belt commences to cooperate isrolled and cooled, characterized in that means are provided at aposition immediately downstream from the point at which the cooperationof the working roll and the metal belt terminates, for applying a gasjet onto the working roll surface in the reverse direction to thedirection of rotation of the roll and, as required, that additionalmeans are provided for applying a gas jet to a portion of the metal beltimmediately downstream from the point of termination of the cooperationin the same direction as that of the tape.

Hereinafter, the preferred embodiments of the invention will bedescribed with reference to the accompanying drawings wherein:

FIG. 1 is an illustration of essentials of a first and a secondembodiment of the invention,

FIG. 2 is an illustration of essentials of a third and a fourthembodiment of the invention,

FIG. 3 is a partial enlarged view of FIG. 2,

FIG. 4 is an illustration of an accident due to a clinging of the tapeto the working roll in the systems as shown in FIGS. 2 and 3.

FIG. 5 is an illustration of a fifth embodiment of the invention.

EMBODIMENT 1

As shown in FIG. 1, a metal belt B1 is passed between a back-up roll R1and a working roll R2. The metal belt B1 and the rolls R1, R2 are madeto run rotate in the arrowed directions. A molten metal M is supplied tothe nip of the metal belt B1 and the working roll R2, and rolled andcooled, under the following conditions, to become an amorphous metaltape T. Symbol G designates a guide roll.

Rolls:

Metal working roll (R2)

100 mm diameter, 40 mm t, mirror finished, ASTM 1045

Elastic back-up roll (R1)

Has two layers of gum tape to a total thickness of 1 mm.

Both the working roll R2 and the back-up roll R1 are supported bybearings to permit free rotation and they are friction driven by thebelt B1. Further, the roll clearance between two rolls R1 and R2 can beadjusted.

Metal belt (B1)--open end type

Brass strip of 65/35 of 0.3 mmt×27 mmw×200 mL

Molten metal

Composition: 83.9% Co-5.3% Fe-8.5% Si-2.3% B (by weight)

Melting:

100 g of the above alloy was melted in a quartz glass tube of 16 mmdiameter having an opening of 1.6 mm diameter at the bottom end, in ahigh frequency induction coil. The molten metal was pressurized to 0.2atm by means of an argon gas. The molten metal was then ejected as a jetstream and introduced into the gap between the roll R2 and the belt B1in an accurate manner.

Condition of rolling

Tension of belt B1: about 6 kg

Speed of roll R1: 1500 rpm

Clearance between roll R1 and belt B1: minus 5/100 mm minus meanssqueezing or shrinking. When the gap between the working roll and theback-up roll is equal to the thickness of the belt, the gap is regardedas being at the zero position. When the axis of one of the rolls drawscloser to the axis of the other roll, from the zero position, the formeraxis is regarded as being a minus position.

Result

A tape having a beautiful surface and uniform dimensions 42μ(t)×10mm(W)×42 m(L) the tailing end of the tape were both found completelycooled. A perfect amorphous nature of the tape was confirmed by abending test and an x-ray examination. In addition, the tape exhibitedthe same satisfactory physical and mechanical properties as are obtainedfor a narrower tape of 2 to 3 mm wide. As to the fluctuation ofthickness, the standard deviation was 2μ both in the longitudinal andthe transverse direction of the tape.

A substantially similar result was obtained with the use of a metal rollsame as the working roll R2 for a back-up roll and at a roll clearanceof -1/100except that the thickness deviation was increased to 3μ, avalue still acceptable. This deviation of thickness was reduced to 2.5by resiliently supporting the back-up roll by a spring.

EMBODIMENT 2

Same system as that shown in FIG. 1 was used but the metal working rollwas replaced by a ceramic roll.

Rolls:

Ceramic working roll (R2)

100 mm diameter 40 mm t, finished by polishing

(A composite roll consisting of an outer alumina ring of 100 diameter×70diameter and an inner steel ring of 70 diameter×40 diameter)

Elastic back-up roll (R1)

A metal roll of 100 diameter coated with a 20 mm thick silicon rubber.

Other conditions being the same as in Embodiment 1.

Result

A tape having substantially the same properties and dimensions as in thefirst test of Embodiment 1 was obtained. No roughening of the ceramicroll surface was observed after the test.

Further, in this embodiment, quartz (solid), zirconia (solid), sapphire,silicon carbide (solid), aluminum nitride and iron nitride (to a depthof 20μ on a ASTM D2 roll) rolls were tested and all found satisfactory.None of them showed surface roughening.

EMBODIMENT 3

The processing was carried out by a method as illustrated in FIGS. 2 and3, in accordance with the following conditions.

Rolls:

Metal working roll (R2)

100 mm diameter×40 mmt, mirror finished

Back-up roll (R1)

Same metal roll as the working roll (R2) but having double surfacelayers of gum tape wound to a total thickness of 1 mm. Both rolls aremade of ASTM 1045, and are supported by bearings, to permit freerotation.

Metal belt (B1)

65/35 brass strip of 0.3 mmt×27 mmW×200 mL

Pay-off reel (C1)

Made of aluminum and equipped with a powder brake.

Starting diameter is 26 cm.

Take-up reel (C3)

Same as the pay-off reel. Driven by a 2 HP variable speed motor at aspeed of about 1,000 rpm.

Guide roll (G4)

60 mm diameter having a groove of 27.5 mm wide and 3 mm deep

Guide roll (G1)

Same as C4

The metal belt B1 starting from the reel C1 is passed via the guide rollG4, onto the back-up roll R1, and through the nip point P between themetal working roll R2 and the back-up roll R1. The belt B1 then turnsaround the metal working roll R2 over a part PQ and is taken up by thereel C3 via the guide roll G1. In the nip point P, is established a facecontact over an arc P1P2 due to the elastic deformation of the back-uproll R1, as will be seen from the enlarged view of FIG. 3. The clearancebetween the rolls R1 and R2 is set to -5/100 mm (symbol-representstightening of the nip or narrowing the clearance, whilesymbol÷represents loosening or widening, the zero (0) clearance meansthe minimum roll gap below which compression by the back-up roll sets inR1.) the tension applied to the metal belt B1 is about 6 kg.

Molten metal

Composition: 83.9% Co-5.3% Fe-8.5% Si-2.3% B (by weight)

Melting:

100 g of the above alloy was melted in a quartz glass tube of 16diameter having an opening of 1.6 mm diameter at the bottom end, in ahigh frequency induction coil. The molten metal (M) was then pressurizedto 0.2 atm by an argon gas, injected and introduced precisely into thegap between the roll R2 and the belt B1.

Result

A tape having substantially the same properties and dimensions as in thefirst test of Embodiment 1 was obtained.

In another test with the use of a 0.22 mm thick soft steel belt and at asomewhat widened roll clearance of -1/100 mm, a tape having a beautifulsurface and dimensions of 30μ(t)×14 mm(W)×40 m(L) was obtained. Nodifference in physical and mechanical properties was detected betweenthe leading and the tailing end.

Still in another test with the use of a metal roll same as the workingroll R2 for a back-up and at a roll gap of -1/100 mm, the thicknessdeviation was increased to 3μ. This could be reduced to 2μ by increasingthe belt tension to 10 kg.

EMBODIMENT 4

The tape was produced by the method as shown in FIGS. 2 and 3, inaccordance with the following conditions.

Rolling condition

Ceramic working roll (R2)

A composite roll consisting of an outer alumina ring of 100 diameterOD×85 diameter ID and an inner metal ring of 85 diameter OD×40 diameterID.

Back-up roll (R1)

A metal roll of 100 diameter coated with a teflon layer of 10 mm thick.The material of roll was ASTM 1045. Other conditions being the same asin Embodiment 3.

Result

A tape having substantially the same properties and dimentions as in thetest of Embodiment 3 was obtained.

Then, tests were carried out in the same condition but the material ofthe ceramic roll substituted by mullite, sapphire, zirconia, beryllia,silica (solid), magnesia, aluminum nitride, boron nitride and nitrogencarbide (solid), and the material of the metal belt substituted byspring steel SK4. Completely amorphous metal tapes were obtained and noroughening of the ceramic roll surface were observed in each case.

EMBODIMENT 5

The critical features of the embodiments 3 and 4 as shown in FIGS. 2 and3 reside in that the guide roll G1 is disposed at the delivery side ofthe roll R2 so that the metal belt B1 may be put into surface contactwith a part of the circumference of the roll R2. However, this techniqueinvolves a problem that the tape (T) is likely to cling to the workingroll R2.

Namely, in the normal state of operation, the rolled tape is carried bythe belt B1 and delivered in the direction of an arrow T1. However, itis often experienced that the tape is delivered in the direction of anarrow T2 to cling the working roll R2, so as to be rolled again.

One of the reason for this clinging accident is that the tape afterrolling inherently has a tendency to cling to the roll R2, because ithas been rolled around the latter. This tendency gets remarkable as thediameter of the roll is reduced and as the contacting area is increased.

The embodiment 5 is prepared for this clinging of the tape to the roll.

Referring to FIG. 5, means are provided for applying a gas jet J1. Thearrangement is such that the gas jet J1 is once directed toward thesurface of the working roll R2, and is then deflected toward the spaceV. This gas jet J1 functions to negate the pressure reduction in thespace V and to press the tape onto the surface of the belt B1 apart fromthe roll R2. In addition to these effects, this gas jet J1 furtherprovides a remarkable effect of cooling of the tape. The medium of thegas jet is preferably air, inert gas and the like, and a pressure of 1to 5 atm is sufficient although it depends on various conditions such asdiameter of the gas nozzle, distance between the nozzle and the space(V), position on the working roll R2 at which the belt B1 comes tocontact and so forth.

The nozzle preferably has an elongated cross-section similar torectangular, rather than circular, so that the jetted gas mayeffectively sweep the roll surface.

For further enhancing the effect of the invention, it is preferred toprovide a sleeve S adapted to cover the running surface of the tape B1at a region between the working roll R2 and the guide roll G1, as shownin FIG. 5, and to make another gas jet J2 flow through the sleeve Stoward the guide roll G1. This conveniently ensures the tape having leftthe roll R2 to be attracted into the sleeve S.

The combined use of the gas jets J1 and J2 is preferred because of theincreased effect of clinging prevention, although the gas jet J1 or J2may be used solely.

Rolling condition

Metal roll (R2)

100 mm diameter, 40 mm t, mirror finished

Back-up roll (R1)

A gum tape is wound doubly around the same roll as the metal roll R2 toform a surface layer of 1 mm thick. ASTM 1045 was used as the materialof both metal rolls R1 and R2. The rolls were rotatably supported bybearings, and the clearance therebetween was made adjustable.

Metal belt (B1)

65/35 brass strip of 0.3 mmt×27 mmW×200 mL

Pay-off reel (C1)

Equipped with powder brake, made of aluminum, initial winding diameteris 26 cm.

Take-up roll (C3)

Same as the reel C1. Driven by a 2 HP variable revolution speed of about1,000 rpm.

Guide roll (G4)

60 mm diameter, Equipped with groove of 27.5 mmW

Guide roll (G1)

Provided with groove, 60 mm diameter

The arrangement was such that the metal belt B1 paid off from the reelC1 is lead to the back-up roll R1 via the guide roll R1 and then passedthrough the nip point P between the back-up roll R1 and the metal rollR2. The belt B1 then makes a turn in contact with a part PQ of thecircumference of the metal roll R2, and is finally taken up by the reelC3 via the guide roll G1. The tension in the belt B1 was about 6 kg asmeasured from the braking electric current.

Gas jet (J1)

This is applied to the surface of the roll R2 immediately downstreamfrom the point at which the belt B1 leaves the roll R2, in thetangential direction of the roll R2 so as to be deflected toward thespace V. The gas of jet has a room temperature and jetted at a pressureof 1 to 5 atm, from a nozzle having a rectangular opening of 10 mm wide.

Condition of molten metal

Composition: 83.9% Co-5.3% Fe-8.5% Si-2.3% B (by weight)

Melting: 100 g of material was molten in a quartz glass of 16 mmdiameter having a bottom nozzle port of 1.6 mm diameter. The moltenmetal was then pressurized by argon gas to a pressure of 0.2 atm and wasinjected and introduced to the point P at which the belt B1 commences tocontact the roll R2.

Result

A tape (T) having an attractive appearance of 4.2μ(t)×10 mm(W)×42 mm(L)was obtained. The leading and the trailing side ends of the tape wasfound to have been cooled completely. Physical characteristics such asmagnetic characteristic and hardness were found acceptable for narrowertape of 2 to 3 mm wide. As to the thickness fluctuation, the thicknessdeviation was as small as 2μ in both breadthwise and longitudinaldirections of the tape.

Tests were carried out in the same condition but neglecting the gas jetJ1. As a result, clinging accident was caused once for each 5 (five)rolling operation. However, when the gas jet J1 was used, no accidentwas caused during about 100 times of repeated rolling operation. Thismeans that the effect of the gas jet J1 is remarkable.

What is claimed is:
 1. A method of producing long, wide amorphous metaltapes having a thickness of less than 0.05 mm, and having a superiordimensional accuracy comprising:introducing a molten jet of acomposition capable of forming an amorphous metal upon rapid coolingdirectly into a contact nip area formed between a first rotating,working roll, whose surface is comprised of metal, and a contiguous,long open-end, flexible metal belt; simultaneously rolling and coolingsaid molten metal on both sides by said working roll and said beltwithin said contact area, said contact being effected by providing asecond, back-up roll whose surface is comprised of elastic material, andwherein said back-up roll presses elastically said metal belt againstsaid working roll, and both rolls being friction-driven by said metalbelt, and wherein said contact nip area formed between said working rolland said metal belt is elastically closed prior to said spraying of saidmolten metal and is elastically expanded by solidified metal passinginto said contact area.
 2. A method of producing long, wide amorphousmetal tapes as in claim 1, further comprising:increasing the surfacecontact area between said working roll and said open-end belt over aportion of the circumference of the surface of said working roll on aside of said working roll from which said tape is being taken up, byproviding a third, guide, roll at a position closer to said working rollthan said back-up roll.
 3. A method for producing a long, wide amorphousmetal tape as put forth in any of claims 1 or 2, furthercomprising:applying a gas to a portion of said working roll surfaceimmediately downstream from a point of the surface circumference of saidworking roll at which said working roll surface departs away from saidmetal belt, said gas jet being applied in a reverse direction to thedirection of rotation of said working roll.
 4. A method of producing along, wide amorphous metal tape having a superior dimensional accuracycomprising:introducing a molten jet of a composition capable of formingan amorphous metal upon rapid cooling directly into a contact nip areabetween a rotating, working roll and a back-up roller, a surface of saidback-up roller pressing a contiguous long open-end, flexible metal beltagainst said working roll; driving said working roller and said back-uproller by said metal belt; simultaneously rolling and cooling saidmolten metal by said working roll and said belt within said nip contactarea; wherein said contact nip area is closed prior to said introductionof said molten material and is expanded by solidified metal passing intosaid contact area.
 5. A method according to claim 4, wherein saidcooling of said amorphous metal is performed primarily by said metalbelt.
 6. A method according to claim 4, wherein said working roller ismetal.
 7. A method according to claim 4, wherein said working roller isceramic.
 8. A method according to claim 4, wherein said pressing is byone of a spring and a hydraulic or penumatic cylinder.
 9. A methodaccording to claim 4 or 6, wherein said surface of said back-up rolleris an elastic material and wherein said back-up roller elasticallypresses said metal belt against said working roller.
 10. A methodaccording to claim 4, wherein the thickness fluctuation of the tape ismaintained within ±2μ for a mean tape thickness of 25μ.
 11. A methodaccording to claim 4, wherein said working roll is a sleeve-like ceramicmaterial combined with a metallic core.